RF extender experiences with RF 100-500 1.4x vs 2.0? Locked

mikepro74 wrote:

I recently picked up the 100-500 lens, which has been great on my R6. Been thinking I should pick up an extender, and trying to decide between the 1.4x and 2.0x.

100-500 with extenders becomes:

420-700mm f/8-10 L IS with 1.4x

600-1,000mm f/11-14 L IS with 2.0x

Seems like the 2.0x converter is the one to get, as the 1.4 only really adds 200mm to your range. The 2.0 converter has no range overlap with the 100-500, so almost like having another lens. But, you do lose an extra stop. How much impact does that have on people?

Just wondering from people who have either, what their experience has been.

That question is not just one about this equipment in particular, but is a general question.

Yes, you lose exposure with the aperture wide open, with the same shutter speed and environmental illumination. No, you do not lose any total subject light with a TC, however, unless you back 1.4x or 2x as far from the subject to fit it in the frame, because you had on a TC that you don't need.

How does the added length of the teleconverter affect balance handling of the 100-500? (.8" vs 1.5" longer)

If doing handheld birds/wildlife, how difficult is subject acquisition at 600mm+ ?

That's down to your experience, how large the subject is in the frame, and how erratically it moves around. The narrower the angle of view, the more likely that when you lift the lens, you don't find the subject in the frame and lose an opportunity, especially when your muscle memory is first learning the gear.

Is 700mm max at one faster stop better (and enough difference over 500mm) to get the 1.4? I have the R6 so can crop in some, but not to extent as say R5....

700/10 is the same aperture as 500/7.1; 71mm. The former puts the subject on 2x as many pixels, though, something most useful with large-pixel sensors. 700/10 is like using (is equivalent to) using the 500/7.1 on a 1.4x crop sensor with 20MP. 1000/14 is like using the 500/7.1 on a 2x crop sensor with 20MP (like m43, but with the 3:2 aspect ratio).

I guess basically if I only plan to buy one, on paper seems like 2.0x is way to go. Anyone have different opinions or feedback I'm not thinking about?

The downside to 2x vs 1.4x is that in the overlapping focal lengths, the 1.4x will have a larger aperture. It is always better to zoom in than to use a TC, if possible, for any given shot, but the versatility of the range of focal lengths dictated by a TC may be more valuable for a range of situations where you have to react quickly. Here is the open f-ratios vs focal length with all three states:

Open f-ratio vs focal length for RF100-500, and with a 1.4x and a 2x TC

If you stop down for a certain DOF, though, you won't have the open f-ratio, and the point is then moot.